//
//  NRWCarRemarkTextView.m
//  New_Runway
//
//  Created by NewLife on 2018/3/13.
//  Copyright © 2018年 NelsonJ. All rights reserved.
//

#import "NRWCarRemarkTextView.h"

@interface NRWCarRemarkTextView()<UITextViewDelegate>

@end

@implementation NRWCarRemarkTextView
{
    UILabel *_rightBottomLabel;
}

- (instancetype)initWithRemarkTextView
{
    self = [super init];
    if (self) {
        
        [self setupUI];
        
        self.layer.borderColor = getColorFromString(@"e1e1e1").CGColor;
        self.layer.borderWidth = 0.5;
        
        self.delegate = self;
        
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textViewDidChange:) name:UITextViewTextDidChangeNotification object:self];
    }
    return self;
}

- (void)setText:(NSString *)text {
    
    [super setText:text];
    
    _rightBottomLabel.text = [NSString stringWithFormat:@"%zd/%zd", text.length,self.maxLength];
}

- (void)setupUI {
    
    _rightBottomLabel = DPLabel()
    .setTextColor(getColorFromString(@"989898"))
    .setFont(kPingFangRegular13())
    .setTextAlignment(NSTextAlignmentRight)
    .setText([NSString stringWithFormat:@"%zd/%zd", self.text.length,self.maxLength]);
    
    self.addSubview(_rightBottomLabel);
}

- (void)layoutSubviews {
    
    [super layoutSubviews];
    
    [_rightBottomLabel sizeToFit];
    _rightBottomLabel.frame = CGRectMake(self.width - 50 - 6, self.height - _rightBottomLabel.height - 3, 50, _rightBottomLabel.height);
}

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range
 replacementText:(NSString *)text
{
    UITextRange *selectedRange = [textView markedTextRange];
    //获取高亮部分
    UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];
    //获取高亮部分内容
    //NSString * selectedtext = [textView textInRange:selectedRange];
    
    //如果有高亮且当前字数开始位置小于最大限制时允许输入
    if (selectedRange && pos) {
        NSInteger startOffset = [textView offsetFromPosition:textView.beginningOfDocument toPosition:selectedRange.start];
        NSInteger endOffset = [textView offsetFromPosition:textView.beginningOfDocument toPosition:selectedRange.end];
        NSRange offsetRange = NSMakeRange(startOffset, endOffset - startOffset);

        if (offsetRange.location < self.maxLength) {
            return YES;
        }
        else
        {
            return NO;
        }
    }
    
    
    NSString *comcatstr = [textView.text stringByReplacingCharactersInRange:range withString:text];
    
    NSInteger caninputlen = self.maxLength - comcatstr.length;
    
    if (caninputlen >= 0)
    {
        return YES;
    }
    else
    {
        NSInteger len = text.length + caninputlen;
        //防止当text.length + caninputlen < 0时，使得rg.length为一个非法最大正数出错
        NSRange rg = {0,MAX(len,0)};
        
        if (rg.length > 0)
        {
            NSString *s = @"";
            //判断是否只普通的字符或asc码(对于中文和表情返回NO)
            BOOL asc = [text canBeConvertedToEncoding:NSASCIIStringEncoding];
            if (asc) {
                s = [text substringWithRange:rg];//因为是ascii码直接取就可以了不会错
            }
            else
            {
                __block NSInteger idx = 0;
                __block NSString  *trimString = @"";//截取出的字串
                //使用字符串遍历，这个方法能准确知道每个emoji是占一个unicode还是两个
                [text enumerateSubstringsInRange:NSMakeRange(0, [text length])
                                         options:NSStringEnumerationByComposedCharacterSequences
                                      usingBlock: ^(NSString* substring, NSRange substringRange, NSRange enclosingRange, BOOL* stop) {
                                          
                                          if (idx >= rg.length) {
                                              *stop = YES; //取出所需要就break，提高效率
                                              return ;
                                          }
                                          
                                          trimString = [trimString stringByAppendingString:substring];
                                          
                                          idx++;
                                      }];
                
                s = trimString;
            }
            //rang是指从当前光标处进行替换处理(注意如果执行此句后面返回的是YES会触发didchange事件)
            [textView setText:[textView.text stringByReplacingCharactersInRange:range withString:s]];
            //既然是超出部分截取了，哪一定是最大限制了。
            _rightBottomLabel.text = [NSString stringWithFormat:@"%zd/%zd",self.maxLength,self.maxLength];
            [self layoutSubviews];
        }
        return NO;
    }
}

- (void)textViewDidChange:(NRWCarRemarkTextView *)textView
{
    
    
    UITextRange *selectedRange = self.markedTextRange;
    //获取高亮部分
    UITextPosition *pos = [self positionFromPosition:selectedRange.start offset:0];
    
    //如果在变化中是高亮部分在变，就不要计算字符了
    if (selectedRange && pos) {
        return;
    }
    
    NSString  *nsTextContent = self.text;
    NSInteger existTextNum = nsTextContent.length;
    
    if (existTextNum > self.maxLength)
    {
        //截取到最大位置的字符(由于超出截部分在should时被处理了所在这里这了提高效率不再判断)
        NSString *s = [nsTextContent substringToIndex:self.maxLength];
        
        [self setText:s];
    }
    
    //不让显示负数 口口日
    _rightBottomLabel.text = [NSString stringWithFormat:@"%ld/%zd",MAX(0,existTextNum),self.maxLength];
    [self layoutSubviews];
}

- (NSInteger)maxLength {
    
    if (_maxLength == 0) {
        _maxLength = 50;
    }
    return _maxLength;
}

@end
